1. Field of the Invention
The present invention relates to a method and an apparatus for manufacturing a hooked fastener part for hook-and-loop fasteners.
1. Prior Art
According to a known method and apparatus of the type described above, a hooked fastener part is produced by cutting loops on a base near the respective outer ends. Hook-shaped material engaging elements thus formed each provide only a small opening through which a loop on a mating looped fastener part is brought into hooking engagement with the hook-shaped engaging element. Such small opening hinders smooth engagement of the hook with the loop, with the result that the possibility of hooking between hooks and loops, i.e., the firmness of engagement of such a hook-and-loop fastener is considerably decreased.
Japanese Patent Publication No. 42-13511, published Aug. 1, 1967 discloses an attempt to provide a relatively large opening with a hook-shaped element. Each loop is cut on it one leg at two different points by means of a pair of parallel spaced upper and lower movable blades and a stationary blade disposed between the movable blades, all the blades being inserted in the loop. The blades need to be thin enough to pass through such small loops and are liable to be damaged or sometimes broken. Furthermore, it has been proven difficult to insert the cutter blades into such loops of irregular shape such as being kinked or collapsed, leaving the loops uncut on the hooked fastener part.